Inking devices for printers



Oct. 10, 1967 Filed Aug. 17. 1965 J. A. RAKOWICZ ETAL INKING DEVICES FORPRINTERS 2 Sheets-Sheet l Oct- 10, 196 I J. A. RAKOWICZ ETAL 3,3 3

INKING DEVICES FOR PRINTERS Filed Aug. 17; 1965 v 2 Sheets-Sheet 2 fie.Z.

United States Patent 3,345,943 INKING DEVICES FOR PRINTERS Jan AntoniRakowicz and Geotfrey Arnold Wark, London, England, assignors to TheMolins Organisation Limited, London, England, a corporation of GreatBritain Filed Aug. 17, 1965, Ser. No. 480,302 Claims priority,application Great Britain, Sept. 1, 1964,

35,783/64' 3 Claims. (CI. 101--366) ABSTRACT OF THE DISCLOSURE Thisinvention relates to a device for feeding ink at a metered rate to apair of inking rollers in a letterpress printer. The device comprises apiston-cylinder arrangement with a nozzle for directing ink to the nipbetween the rollers, the piston being driven by the intermittentrotation of a screw member which itself is driven by a sprag clutch andlever arrangement, thelever being driven by the letterpress printer.Means is provided for adjusting the effective length of the lever toregulate the amount of rotation of the sprag clutch with each stroke.Also means is provided for conveniently resetting the means for drivingthe piston when the supply of ink has been exhausted from-thecylinderand is being refilled.

This invention concerns improvements in inking devices for printers andhas among its objects to provide a device which can operate at a highspeed without the risk of ink splashing and arranged to meter the ink,so that very fine printing can be achieved with uniform colour anddensity.

According to the invention an inking device for a letterpress printercomprises a pair of inking rollers running in contact and a fine nozzlearranged to fit in the nip of the two rollers so that a tiny wedge ofink is contained between the rollers and the nozzle, with means forfeeding ink through the nozzle at a metered rate, depending upon thedesired rate of consumption.

The nozzle may form part of a syringe, with means for feeding the pistonof the syringe at the desired rate and the body of the syringe may beinsulated so as to preserve the viscosity of the ink at the desiredvalue, in spite of any changes in ambient temperature.

The nozzle referred to above may be the kind of nozzle used inhypodermic syringes and the syringe itself may be a hypodermic, with acapacity suitable for providing ink for any desired period of time. Thepiston may be pushed through the cylinder of the syringe by power drivenmeans such as gearing driven by a variable speed electric motor, or bymechanism coupled to some other part of the printing machine.

The piston movement may be continuous or intermittent and examples ofboth arrangements are given later.

The invention will be more fully described with reference to theaccompanying drawings, in which:

FIGURE 1 is an elevation, partly in section, of a portion of a printingmachine embodying the invention;

FIGURE 2 is an elevationof part of a printing machine in which theink-feeding arrangements differ somewhat from those shown in FIGURE 1;

FIGURE 3 is a view of a fragment of FIGURE 2 looking in the direction ofthe arrow A, part of the frame of the machine being in section; and

FIGURE 4 is an end elevation of FIGURE 3.

Referring first to FIGURE 1, 1 is a web which is to be printed and it isguided by a pair of rollers 2, one of which runs near a letterpress die3 which, as shown, has four printing surfaces 4 on it. The printingsurfaces receive ink from a small roller 5 and this in turn reice ceivesink from a large distributing roller 6, which re-- ciprocates on itsshaft with distributors 7 operating on parts of its circumference.Beneath the roller 6 is another roller 17 and these two run in closecontact and in the nip of the rollers there is arranged a nozzle '8,which may be the nozzle of a hypodermic syringe, or some small nozzlesuitable to enter between the nip of the rollers, and arranged vertuallyin contact with them. In fact there is a small clearance to avoid wearon the syringe nozzle and to clear the ink layer. The nozzle forms partof a syringe 9 which has a piston 10 having a piston rod 11 with aspring 12 tending to withdraw the piston from the neighbourhood of thenozzle. The syringe body is clamped in position as shown.

The piston rod 11 is engaged by a finely threaded screw 13 which worksin an axially fixed nut consisting of a gear wheel 14 and this isrotated to feed the screw and drive the piston forward by means of agear wheel 15 driven by a variable speed motor 16. The screw isprevented from rotating by a spline or the like not shown.

In operation the speed of the motor is adjusted so that the quantity ofink fed through the nozzle is exactly that required to provide adequateink to the four printing surfaces of the roller 3 and the location ofthe nozzle is such that between the rollers 6 and 17 there is a tinywedge of ink which cannot escape, since it is in a virtually closedcompartment and thus there is no risk of ink splashing. The ink fedthrough the nozzle to the roller 6 is distributed over the roller 6 bythe distributors 7 and a thin film of ink is provided to the transferroller 5 and applied to the printing surfaces of the roller 3. Ifdesired the rollers 7 may be reciprocated axially to distribute the inkon roller 6 which then has no axial movement.

As shown, the syringe is large enough to contain a quantity of inksuitable for a run of a desired time, say several days, and the body maybe surrounded by suitable lagging so as to keep the temperature withinthe interior of the syringe at a uniform level and retain the viscosityof the ink at a desired value.

It will be seen that in this example the piston 10 is movedcontinuously.

Referring now to FIGURE 2, the ink is fed as before through a nozzle 18,into the nip of a roller 19 and a larger roller 20. A distributor roller21 which reciprocates axially spreads the ink on the roller 20.

Ink on roller 20 is transferred to a further roller 25 which applies theink to the letterpress die roller 26 which has printing surfaces 27 onit. The roller 25 is supported on a quadrant-shaped plate 22, pivoted onthe shaft of roller 20 and adjustable on the pivot by a screw 24. Inthis way the roller 25 can be moved to adjust its pressure against theprinting surfaces 27.

The paper web 28 passes around rollers 29, 30 and 31, the roller 30being carried on a lever 30A, pivoted at 32 and adjustable on the pivotby a screw 33 and spring 34. In this way the web can be brought into thedesired contact with the printing surfaces 27 Ink is fed through thenozzle 18 by a piston 35, fixed to a piston rod 36, and movable in thebody of a syringe 37, the movement being effected by a screw 38 whichhas a nut 39 on it arranged to press on the end of the piston rod. Thescrew is rotated intermittently by a connecting rod 40 driven by a crankdisc 41 which is r0- tated from the machine driving mechanism by a shaft42 driven through bevel gear wheels 43 one of which is fixed to a shaft44, driven by said mechanism. The end of the connecting rod 40 remotefrom the crank disc is adjustably connected to a lever 45 which drives asprag clutch 46, to the driven member of which the screw 38 is fixed.The lever 45 has a nut 47 slidable in a slot 48 of the lever and theposition of the nut can be altered by a screw 49, thus altering thethrow of the sprag clutch and the amount of rotation of the screw foreach revolution of the crank disc 41.

In order to avoid the necessity of winding the nut 39 back along thescrew 38 when it reaches the end of the thread, the nut has two holes init which intersect. One hole 50 is tapped to suit the thread of thescrew 38 and the other 51 is a clearance hole. By rocking the nut theclearance hole may be aligned with the screw and the nut can then beslid back to the starting position.

This arrangement therefore provides an adjustable intermittent feed ofthe ink.

If desired a temperature controller of any known kind may be providedfor controlling the viscosity of the ink in the syringe and in eitherconstruction the mechanism for moving this piston may be controlled by adevice which scans the printed web and regulates the ink flow asnecessary to keep the print to a desired density.

It will be seen that the ink supply is dust proof and the arrangementsshown are suitable for use with a variety of inks with differingviscosities.

Because the ink supply is virtually closed against evaporation there isno change in the colour of the ink, which can occur When a solventevaporates from an open ink vessel.

While the invention has been described as applied to the feeding of inkfor printing it can be used for feeding adhesives where the accurateapplication of desired quantities of adhesive is necessary.

Alternatively any other suitable means may be provided for feeding inkto the nozzle, for example a pump such as is used for feeding fuel tosome I.C. engines.

The above description has dealt mainly with a small nozzle such as isused in a hypodermic syringe and this is adequate for such work asprinting cigarette webs where a line of small type is all that isrequired but for wider work a series of such nozzles may be used, sideby side, or a nozzle of the width required to go into the nip of theinking rollers and extending lengthwise of the rollers for the distancerequired may be used.

What we claim as our invention and desire to secure by Letters Patentis:

1. An inking device for a letterpress printer comprising a pair ofinking rollers mounted for running in contact with each other, apiston-cylinder arrangement for containing and feeding an ink supply, afine nozzle arranged to fit in the nip of the two rollers, conduit meansconnecting said cylinder with said nozzle, and power driven meansoperatively connected to said piston to move said piston through saidcylinder for feeding ink at a metered rate from said cylinder throughsaid nozzle to maintain a small wedge of ink in said nip, said powerdriven means comprising a crank device operatively connected to anddriven by said letterpress printer, a rod secured to said piston, anaxially fixed screw having a nut thereon which presses against said rodwhereby rotation of said screw causes said nut, rod and piston to move,a sprag clutch secured to said screw, a lever for driving said clutchand a connecting rod secured to said lever and operatively connected tosaid letterpress printer whereby said screw is intermittently rotatable.

2. An inking device as claimed in claim 1 further comprising means foraltering the throw of said sprag clutch, said means comprising a slot insaid lever, a second nut in said slot and secured to said connectingrod, a manually rotatable screw operatively connected to said secondnut, whereby adjustment of said screw and resultant adjustment of saidsecond nut regulates the effective length of said lever and its angularmovement with each stroke of the connecting rod.

3. An inking device as claimed in claim 1 in which the nut on theaxially fixed screw has a threaded hole to engage the screw and a plainhole intersecting the threaded hole whereby the nut may be rocked on thescrew to move the threaded hole out of engagement with the screw andalign the plain hole therewith so that the nut may be slid back alongthe screw when it reaches the end of its advancing movement on thescrew.

References Cited UNITED STATES PATENTS 2,312,140 6/1943 Grupe 1012l92,676,563 4/ 1954 Montgomery et al. l18249 X 3,199,451 8/1965 Nitchie101366 ROBERT E. PULFREY, Primary Examiner.

F. A. WINANS, Assistant Examiner.

1. AN INKING DEVICE FOR A LETTERPRESS PRINTER COMPRISING A PAIR OFINKING ROLLERS MOUNTED FOR RUNNING IN CONTACT WITH EACH OTHER, APISTON-CYLINDER ARRANGEMENT FOR CONTAINING AND FEEDING AN INK SUPPLY, AFINE NOZZLE ARRANGED TO FIT IN THE NIP OF THE TWO ROLLERS, CONDUIT MEANSCONNECTING SAID CYLINDER WITH SAID NOZZLE AND POWER DRIVEN MEANSOPERATIVELY CONNECTED TO SAID PISTON TO MOVE SAID PISTON THROUGH SAIDCYLINDER FOR FEEDING INK AT A METERED RATE FROM SAID CYLINDER THROUGHSAID NOZZLE TO MAINTAIN A SMALL WEDGE OF INK IN SAID NIP, SAID POWERDRIVEN MEANS COMPRISING A CRANK DEVICE OPERATIVELY CONNECTED TO ANDDRIVEN BY SAID LETTERPRESS PRINTER, A ROD SECURED TO SAID PISTON, ANAXIALLY FIXED SCREW HAVING A NUT THEREON WHICH PRESSES AGAINST SAID RODWHEREBY ROTATION OF SAID SCREW CAUSES SAID NUT, ROD AND PISTON TO MOVE,A SPRAG CLUTCH SECURED TO SAID SCREW, A LEVER FOR DRIVING SAID CLUTCHAND A CONNECTING ROD SECURED TO SAID LEVER AND OPERATIVELY CONNECTED TOSAID LETTERPRESS PRINTER WHEREBY SAID SCREW IS INTERMITTENTLY ROTATABLE.